1. Field of the Invention
The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device.
Note that in this specification and the like, the semiconductor device refers to any devices that can function by utilizing semiconductor characteristics, and an electro-optical device, a light-emitting display device, a semiconductor circuit, and an electronic device are all included in the category of the semiconductor device.
2. Description of the Related Art
Attention has been focused on a technique for forming a transistor using a semiconductor thin film which is formed on a substrate having an insulating surface. The transistor has been widely used for semiconductor electronic devices such as integrated circuits (ICs) and image display devices (also simply referred to as display devices). A silicon-based semiconductor material is commonly known as a material for a semiconductor thin film applicable to a transistor. As another material, an oxide semiconductor has been attracting attention.
For example, Patent Document 1 and Patent Document 2 disclose a technique in which a transistor is manufactured using zinc oxide or an In—Ga—Zn-based oxide as an oxide semiconductor and such a transistor is used as a switching element or the like of a pixel of a display device.
Further, Patent Document 3 and Patent Document 4 disclose a technique in which an oxide semiconductor thin film is formed by a coating method such as an ink-jet method.